Correct DTH for Dimmers and Switches

ST has been adding a large number of new DTHs over the past year which is great as it usually means support for new hardware. However, due to the lack of a description it is becoming increasingly hard to know which DTH is the most appropriate one. ST really needs to improve the DTH selection method as a mere list of DTHs in the drop down is just not scalable and/or useful. You can’t tell for sure which DTHs in the list are official and which have been added by you (although they seem to appear at the bottom), and you can’t tell which one is correct given the poor naming convention (or lack thereof). Now we even have overlapping DTHs to make things more interesting.

An example… and I am seeking advice on which DTH is most appropriate:

All of my switches and dimmers are one of these two devices:

Dimmers - Leviton VRMX1-1LZ 1000W Vizia RF Z-Wave Universal Scene Capable Dimmer, White/Ivory/Light Almond
Switches - Leviton VRS15-1LZ Vizia RF + 15A Scene Capable Switch, White/Ivory/Light Almond

Both of these devices are part of the Vizia RF + line as I wanted to be sure I had the “instant update” feature.

At first, when adding them to ST, the DTH that was picked automatically was:

Dimmers - Dimmer Switch
Switches - Z-Wave Switch

However, more recently the default DTH has changed to:

Dimmers - Z-Wave Dimmer Switch Generic
Switches - Z-Wave Switch Generic

The source code of ST’s DTHs is found here:

SmartThings Github repository for DTHs

At a glance these are the DTHs that might apply to my switches and dimmers:

dimmer-switch.src DVCSMP-2221 - Replace display with displayed (#1457)
secure-dimmer.src Initial commit
zwave-dimmer-switch-generic.src [CHF-459] Health documentation include DTH execution location and exp…
zwave-switch-generic.src [CHF-459] Health documentation include DTH execution location and exp…
zwave-switch-secure.src Initial commit
zwave-switch.src DVCSMP-2221 - Replace display with displayed (#1457)

The read me of the DTH provides a list of which devices are officially supported but I doubt it is comprehensive. The read me also stated whether the DTH allowed for local execution or only cloud execution which I found surprising as I was under the impression all DTHs for switches and dimmers written by ST were automatically approved for local execution.

The most current DTHs seem to be the ones labeled as “generic” but the read me says they are for cloud execution (undesirable) I wonder if I am actually getting the “instant update” benefit of the specific dimmers/switches I purchased given the read me only references the (once) cheaper non Vizia RF + models.

Check out the read me documents:



On the other hand, the older DTH called “Dimmer Switch” is marked as “Local Execution on V2 Hubs” but has absolutely no mention of Leviton dimmers and switches - only GE stuff.


So… which one is the correct one? Why do they have such a mess in their DTHs? Would be nice if someone from ST commented and cleared things up a bit :slight_smile:

1 Like

Try the ones marked as local, if they work and status updates are sufficiently fast, I would just call it a day.
I understand your frustration, but at the end of the day, the correct dth is the one that works and meets your needs.

1 Like

Since I went out of my way to buy the Vizia RF + version of the dimmers and switches I’d like to be sure I am taking advantage of the instant update. It seems like I am but I can’t be sure. I am assuming that for this to work the DTH must support the feature… or is it just a low level protocol thing that happens regardless of DTH?

I have some automations based on the change of status of dimmers/switches so instant update should help reduce the lag. When these automations run locally they are not bad but for some reason they seem to get kicked off occasionally (greater lag).

I’d also like to understand the logic behind having those different DTHs when supposedly all the dimmers pretty much support the same basic features… and why some DTHs are marked for cloud execution versus local execution.

Instant update (or not) is a function of the hardware, not the DTH.

They should be consistent if running locally, so there might be something in your setup that isn’t…

This is a question for support, I have no idea. I know they’re introducing some additional features (heartbeat etc), but why ST keeps dinking with these, and insists on not placing version numbers in the DTH header is beyond me…

1 Like

Great to hear instant update is hardware based… this eliminates some of my concerns with which DTH to adopt. I’ll set all of my dimmers/switches to the ones marked for local execution but first I will review what devices are actually showing up as running local to see if any with the other DTH happen to show up (yup I am not fully trusting the read me files…).

The lags I mostly notice are those where I have the system turn on one light based on another that I switched on manually.

A likely common example due to the uber simple wiring many american houses have (single switch for each light) is what I did to address the issue of having to walk all the way back to the foyer to turn the light off once I got to the main living area in my house upon entering. I’ll try to explain… When I enter my home, I typically would have to turn on my foyer light, then the hall lights, and then the kitchen lights. Once I get to the kitchen I would have to walk back to the foyer to turn the light off, then to the hall to turn the hall light off and then back to the already lit kitchen. I programmed the system to turn on/off my foyer and hall lights together so that when I enter my home I can just turn on my foyer light as the hall lights will turn on automatically. Once I turn on the kitchen light, I can just turn off the much closer hall light switch which will turn off my foyer light as well. Sure, there are other solutions but linking the two lights together was the less disruptive solution. If it doesn’t work no drama unlike some others that go way overboard and when stuff doesn’t work, the house goes nuts :wink:

To explain my comment on “uber simple wiring many american homes have”… I come from Italy and there, even the most basic house, is built with electrical systems that allow you to turn on/off the main lights of every room from ANY door in the room. If a room as 3 doors to enter it, then next to each door there will be a switch to turn on/off the light of that room and just outside each door, there will be switches to do the same for the next room the door leads to. You can walk from point A to point B in a house with rarely ever having to go back to turn a light off. There is way more to my comment but it is not pertinent to home automation.

Ditto! Would be nice if they adopted versioning with decent changelogs…